Yarn core

ABSTRACT

A yarn core has a start-up groove of V-shaped cross-section located near an outboard end of the core. A yarn latch is formed on the inboard wall of the groove for snagging the yarn. The yarn latch is located in a transition portion of the groove between a wider lead-in portion and a narrower clamping portion. The latch projects from the inboard wall generally in the direction of core rotation and extends partway across the width of the groove toward the outboard wall of the groove.

FIELD OF THE INVENTION

The invention relates to yarn cores on which yarn is wound duringmanufacture, and more particularly relates to yarn cores having astart-up groove for catching and clamping the yarn to start the windingprocess.

BACKGROUND OF THE INVENTION

Yarn cores are employed in the textile industry for winding andsupporting yarn packages. In the package forming process, a moving yarnline is strung up onto a rapidly rotating empty core. In the manualstring-up process, the moving yarn line is usually held by an aspiratorgun and the yarn line brought into tangential contact with the rotatingempty core. Typically, a start-up groove is provided in the surface ofthe core, normally adjacent to one end of the core. The yarn line ismanually directed by movement of the aspirator gun into the groove,which grips the yarn line thereby initiating the wind-up process. Bothco-current and counter-current string-up processes are used in thetextile industry. In the co-current process, the yarn is moving in thesame direction as the core rotation as the yarn is led into engagementwith the core for catching in the start-up groove. In thecounter-current process, the yarn is moving in the opposite direction tothe core rotation.

Newer winder technologies provide for the string-up process to beautomatically initiated without manual intervention. For example withturret-type winders, an empty yarn core is moved from a waiting positionto a winding position when a fully wound yarn package is formed onanother position on the apparatus. The empty core is rotated rapidly andmoved into tangential contact with the thread line being wound on theother, now full yarn package. This initiates string-up for the emptycore and terminates winding for the fully wound core. For this automatedprocess to work effectively, the start-up groove on the empty core mustreadily and reliably catch the incoming yarn line without operatorintervention.

Multiple-width start-up grooves in yarn cores have been provided in aneffort to improve the yarn pick up propensities of the yarn groove. Inthe multiple-width start-up grooves, one lengthwise portion of thegroove is relatively wide while an adjacent lengthwise portion isrelatively narrow. The core is rotated so that the wide portion of thegroove forms the leading portion; the narrow portion of the groove formsthe trailing portion. The transition portion of the groove forms a “nip”for gripping and catching the yarn.

In the textile industry, yarn manufacturing and wind-up speeds havecontinually increased. Moreover, in many cases, yarn propertiesincluding yarn strengths have increased. As yarn manufacturing speedshave increased, the need for improved gripping action by the start-upgroove in the textile cores has also increased. Moreover, in the case ofautomated string-up winders, the gripping action of the start-up groovemust be extremely reliable so that the yarn line can be readily grippedand severed without operator intervention. However, it has been foundthat conventionally formed start-up grooves in textile yarn cores do notalways reliably and repeatably perform these functions, particularlywhen used with different sized yarns, with yarns of different strengths,and/or with automated winding devices operating at high speeds. When astring-up operation fails because the start-up groove fails to properlycatch and grip the yarn, the failure represents a significant disruptionto the winding process and substantial downtime can result.

SUMMARY OF THE INVENTION

The present invention addresses the above needs and achieves otheradvantages by providing a yarn core having a start-up groove in which aspecially configured yarn latch is formed for snagging the yarn so thatthe yarn is much less likely to skip back out of the groove, therebysignificantly improving the string-up efficiency of the core. Yarn coresin accordance with the invention have achieved string-up efficiencies(percentage of attempted string-ups that are successful) of 99 percentor better.

In accordance with one embodiment of the invention, a yarn corecomprises a tubular core having an outboard end and an inboard end. Ayarn start-up groove is formed in the outer surface of the core wallproximate the outboard end thereof. The start-up groove comprises agenerally V-shaped groove formed in the outer surface of the core wallpartway through the thickness thereof, the groove having opposinginboard and outboard walls wherein the inboard wall faces generallytoward the outboard end of the core. The groove comprises a relativelywide V-shaped lead-in groove that leads to a relatively narrow V-shapedclamping groove, with a V-shaped transition groove extending between thetrailing end of the lead-in groove and the leading end of the clampinggroove. A yarn latch is located in the transition groove, the yarn latchcomprising a tapering protrusion projecting from the inboard wall of thegroove generally in the rotation direction of the core wall andextending toward the outboard wall of the groove partway across a widthdefined between the inboard and outboard walls. The yarn latch serves tosnag a yarn led into the lead-in groove.

In a preferred embodiment of the invention, the inboard and outboardwalls of the lead-in and transition grooves are depressed below theouter surface of the core wall while the yarn latch is substantiallyundepressed below the outer surface. The latch thus stands out tomore-readily snag the yarn.

Advantageously, the lead-in groove in cross-section defines a radiallyouter portion having the inboard and outboard walls sloped relativelyshallowly toward each other, and a radially inner portion having theinboard and outboard walls sloped relatively steeply toward each otherand coming together at a bottom of the lead-in groove. The transitiongroove advantageously has a similar configuration.

In a preferred embodiment, the yarn start-up groove extends about morethan half the circumference of the core. The lead-in groove extendsabout at least one-quarter of the circumference of the core. Preferably,the lead-in groove has a constant width except for a tapered portion atthe leading end of the lead-in groove. The clamping groove has aconstant width along substantially the entire length thereof.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a fragmentary perspective view of an outboard end portion of ayarn core in accordance with one embodiment of the invention;

FIG. 2 a fragmentary front elevation of the outboard end portion of theyarn core of FIG. 1;

FIG. 3 is magnified elevation of the transition portion and yarn latchof the yarn core;

FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 2 through thelead-in portion of the start-up groove of the yarn core;

FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 2 through thetransition portion of the start-up groove of the yarn core, showing theyarn latch in further detail;

FIG. 6 is a cross-sectional view taken on line 6-6 of FIG. 2 through theclamping portion of the start-up groove of the yarn core;

FIG. 7A depicts a beginning of a string-up process with a yarn core inaccordance with one embodiment of the invention, showing a yarn beingled into the start-up groove;

FIG. 7B depicts the string-up process at a slightly later instant intime, showing the yarn being engaged by the yarn latch; and

FIG. 7C depicts the string-up process at a still later instant in timeat which the yarn has been successfully snagged by the yarn latch andhas been severed from the trailing end.

DETAILED DESCRIPTION OF THE INVENTION

The present inventions now will be described more fully hereinafter withreference to the accompanying drawings, in which some but not allembodiments of the invention are shown. Indeed, these inventions may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

FIGS. 1, 2 and 3 illustrate a preferred textile core 10 according to theinvention which includes a multiple width start-up groove 12. The core10 is a tubular body formed from paperboard, e.g., spirally woundpaperboard, plastic, or the like. Although illustrated as having acylindrical shape, it will be apparent that the tubular body could alsohave a frustroconical or other shape. Typically a cylindrical textilecore will have an outside diameter of from about two inches up to aboutseven inches, and a wall thickness of from about one-sixth inch up toabout one-half inch.

The multiple width start-up groove 12 in core 10 includes a wide lead-inportion 14, a transition portion 15, and a narrower trailing end orclamping portion 16. As illustrated in FIGS. 7A-7C, further describedbelow, a moving yarn line 18 is contacted first with the lead-in portion14 of groove 12 and thereafter encounters the transition portion 15 andthen the narrower trailing end portion 16 of groove 12. As the yarn line18 encounters the narrower portion of the groove the yarn line isgripped by the groove and severed for initiation of winding of the yarnline 18 onto the core 10. As further described below, the start-upgroove 12 includes a yarn latch to assist in snagging the yarn andpreventing the yarn from skipping back out of the start-up groove.

The groove 12 in the illustrated embodiment extends around more thathalf the circumference of the tube 10, for example, about 235 degrees.In the illustrated embodiment, the lead-in portion 14 of the grooveconstitutes somewhat less than half (e.g., about 90 degrees) of thetotal circumferential extent of the groove while the clamping portion 16of the groove constitutes somewhat more than half (e.g., about 135degrees) of the circumferential extent of the groove; alternatively, thelead-in and clamping portions can be of about equal length, or thelead-in portion's length could exceed that of the clamping portion. Itwill also be apparent to the skilled artisan that the total length ofthe groove 12 can be greater or less than half the circumference of thetube 10. Generally, it is preferred that the groove not extend aroundthe full periphery of the tube so that the strength of the tube is notweakened. However, the length of the groove can readily be extended ifdesired. In addition, two wider, lead-in groove portions 14 can beprovided, one on each end of the narrower portion 16 of the groove asexplained in greater detail in U.S. Pat. No. 4,369,933 to Bedenbaugh andU.S. Pat. No. 4,371,130 to Case, which patents are incorporated hereinby reference.

FIGS. 4 and 6 illustrate, respectively, the cross-sections of the wider,lead-in portion 14 of the groove and the narrower trailing end portion16 of the groove. In cross section, the wide lead-in portion 14 of thegroove is generally V-shaped and has two sidewalls disposed on oppositesides of a center line 22 which extends radially into the tubular body10. Each of the sidewalls are compound sidewalls having a first surface24 extending upwardly from the bottom 26 of the groove and forming anacute angle α₁ with the center line. A second surface 32 of eachcompound sidewall extends downwardly from the top of the groove 14 anddefines a second predetermined acute angle α₂ with axis 22 of groove 14.

Advantageously, the angle α₁ formed between the bottom portion 24 of thecompound sidewall and the center line 22 of the groove can range fromless than about 5° up to about 15°, preferably 5° to 10°, while theangle α₂ formed between the upper portion of the sidewall 32 and thecenter line 22 can range from less than about 15° up to about 45°,preferably from about 25° to about 35°. These ranges are preferred whenboth sidewalls of the groove 14 are angled with respect to the centerline 22. In some cases, one sidewall may be essentially vertical andonly the other of the sidewalls will be an angled wall. In the eventthat only one of the sidewalls is an angled, compound sidewall, then theangles formed by the bottom wall portion and the top wall portion withthe center line will typically be greater than described above.

The compound angle groove illustrated in FIG. 4 is believed to readilyaccommodate yarns having any of various counts or deniers, ranging onthe denier scale, for example, from 30 denier or less up to 2,000 denieror greater. In this regard, the wider portion of the groove at the topthereof is able to receive and grip larger yarns while the narrowerportion of the groove at the bottom thereof is capable of receiving andgripping smaller size yarns.

The cross-section of the narrower clamping portion 16 of the groove 12is seen in FIG. 6. Advantageously, this groove portion includes twosimple or straight angled walls 40, each of which forms an acute angleα₃ with center line 22 of the groove 16. Typically, when there are twoangled sidewalls as illustrated in FIG. 5, the angle α₃ formed by eachsidewall and the center line 22 will range from less than about 50, upto about 20°, preferably from about 5° to about 100. If only onesidewall is angled, then the angle formed by the sidewall and the centerline of the groove will range from about 10° up to about 45°, preferablyfrom about 10° to about 20°.

FIGS. 3 and 5 depict the transition portion 15 of the groove. Thetransition portion has an outboard wall (i.e., the wall closer to theoutboard end of the tube) that is a compound angled wall similar to thewalls of the wide lead-in portion 14 of the groove. Thus, the outboardwall has a lower sidewall 42 forming a relatively small acute angle withthe center line 22 of the groove; this angle can be in the same range asthat given for α₁ above. The outboard wall has an upper sidewall 44forming a relatively larger acute angle with the center line; this anglecan be in the same range as that given for α₂ above. The sidewalls 42and 44 thus can be regarded as extensions of the sidewalls 24 and 32 ofthe wide portion 14 of the groove. The inboard wall of the transitionportion 15 has a lower sidewall 46 that forms a relatively small acuteangle with the center line 22, similar to the angle of the outboardlower sidewall 42. An upper sidewall 48 of the inboard wall forms anacute angle with the center line essentially the same as the angle ofthe lower sidewall 46; thus, the lower sidewall 46 and upper sidewall 48together constitute a wall that extends from the bottom of the grooveupward to the cylindrical outer surface of the core 10 at an essentiallyconstant acute angle relative to the center line. The inboard wall ofthe transition portion 15 also defines a yarn latch 50 (best seen inFIG. 3) to assist in snagging a yarn 18. The yarn latch 50 comprises agenerally triangular-shaped finger of material that projects from theinboard wall of the groove toward the outboard wall of the groove; thesharp vertex of the latch points generally in the rotation direction ofthe yarn core. The yarn latch is formed by two walls, one of which isthe upper sidewall 48 described above; the other wall 52 (FIG. 3)extends from the vertex of the latch in a direction (generally oppositeto the rotation direction) that is angled with respect to thecircumferential direction and joins the upper sidewall 32 of the inboardwall of the groove. Accordingly, there is a space 54 defined between thewall 52 and the wall 32. The top surface of the yarn latch is level withthe cylindrical outer surface of the yarn core, whereas the wall 32 isdepressed below the cylindrical outer surface. Consequently, the space54 narrows in the direction opposite to the rotation direction of theyarn core and also narrows in the depth direction of the groove. Theyarn 18 is snagged by the yarn latch 50 during a string-up operation bywedging in the narrowing space 54.

FIG. 7A through 7C depict a yarn string-up operation using the yarn core10. The start of the string-up operation is shown in FIG. 7A. A yarn 18is directed from a texturizer or other processing device by means of avacuum aspirator (not shown) and is lead by a mechanical hook (notshown) or the like into the groove 12 of the rapidly rotating yarn core;the yarn travels in a direction opposite to the rotation of the core.The yarn drops into the wide lead-in portion 14 of the groove and is inturn led into the transition portion 15 and narrow clamping portion 16of the groove. As the core continues to rotate, as shown in FIG. 7B, theyarn wedges in the space between the yarn latch 50 and the inboard wallof the groove and becomes trapped by the latch. With still furtherrotation of the core, as shown in FIG. 7C, the yarn begins to windaround the core and is thereby pulled back from the vacuum aspirator anddrawn over a cutting blade (not shown) or the like so as to sever theleading portion of the yarn to create a tail end 18′; the yarn comingfrom the texturizer is then wound about the yarn core.

The design of the yarn start-up groove 12 with the yarn latch 50 inaccordance with the invention has been found to significantly improvestring-up efficiency relative to yarn cores such as described in theaforementioned U.S. Pat. No. 5,211,354. Yarn cores in accordance withthe invention have achieved string-up efficiencies (percentage ofattempted string-ups that are successful) of 99 percent or more.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

1. A yarn core for winding yarn wherein a yarn string-up process isemployed for attaching a yarn to the core to begin winding the yarn ontothe core, the yarn core comprising: a tubular core having an outboardend and an inboard end, a wall of the core having an outer surface andan inner surface with a thickness defined therebetween, a yarn start-upgroove being formed in the outer surface of the core wall proximate theoutboard end thereof, wherein the start-up groove comprises a generallyV-shaped groove formed in the outer surface of the core wall partwaythrough the thickness thereof, the groove having opposing inboard andoutboard walls wherein the inboard wall faces generally toward theoutboard end of the core, the groove comprising: a relatively wideV-shaped lead-in groove extending circumferentially from a leading endto a trailing end thereof with respect to a rotation direction of thecore wall; a relatively narrow V-shaped clamping groove extendingcircumferentially from a leading end to a trailing end thereof withrespect to the rotation direction of the core wall, the leading end ofthe clamping groove being located proximate the trailing end of thelead-in groove; a V-shaped transition groove extending between thetrailing end of the lead-in groove and the leading end of the clampinggroove; and a yarn latch located in the transition groove, the yarnlatch comprising a tapering protrusion projecting from the inboard wallof the groove generally in the rotation direction of the core wall andextending toward the outboard wall of the groove partway across a widthdefined between the inboard and outboard walls, the yarn latch servingto snag a yarn led into the lead-in groove.
 2. The yarn core of claim 1,wherein the inboard and outboard walls of the lead-in and transitiongrooves are depressed below the outer surface of the core wall while theyarn latch is substantially undepressed below the outer surface.
 3. Theyarn core of claim 1, wherein the lead-in groove in cross-sectiondefines a radially outer portion having the inboard and outboard wallssloped relatively shallowly toward each other, and a radially innerportion having the inboard and outboard walls sloped relatively steeplytoward each other and coming together at a bottom of the lead-in groove.4. The yarn core of claim 3, wherein the transition groove incross-section defines a radially outer portion having the inboard andoutboard walls sloped relatively shallowly toward each other, and aradially inner portion having the inboard and outboard walls slopedrelatively steeply toward each other and coming together at a bottom ofthe transition groove.
 5. The yarn core of claim 1, wherein the yarnstart-up groove extends about more than half the circumference of thecore.
 6. The yarn core of claim 5, wherein the lead-in groove extendsabout at least one-quarter of the circumference of the core.
 7. The yarncore of claim 1, wherein the lead-in groove has a constant width exceptfor a tapered portion at the leading end of the lead-in groove.
 8. Theyarn core of claim 7, wherein the clamping groove has a constant widthalong substantially the entire length thereof.
 9. The yarn core of claim1, wherein the yarn latch is formed by a first wall that extends from abottom of the start-up groove radially outwardly to the outer surface ofthe core wall at an inclined angle and a second wall that intersects thefirst wall at a tip of the yarn latch and extends from the tip in adirection generally opposite to the rotation direction of the core andat an angle relative to a circumferential direction of the core andintersects with a third wall comprising the inboard wall of the start-upgroove, a narrowing space being defined between the second and thirdwalls in which the yarn is wedged during a string-up operation.
 10. Theyarn core of claim 9, wherein the third wall is inclined relative to aradial direction and is depressed below the outer surface of the corewall.
 11. The yarn core of claim 10, wherein the second wall extendsfrom the bottom of the start-up groove radially outwardly to the outersurface of the core wall.